$\sum\limits_{k=1}^{3 }{{(k-4)}}=$
Answer: What is the question asking for? $\sum$ tells us to find the sum. The question is asking for the sum of the values of $k-4$ from $k = 1$ to $k = 3$. Evaluating $\begin{aligned} \sum\limits_{k=1}^{3 }{({k-4})}&= (1-4) + (2-4) + (3-4) \\\\ &= -3 + (-2) + (-1) \\\\ &= -6\end{aligned}$ The answer $\sum\limits_{k=1}^{3 }{({k-4})}=-6$